Growth of epiphytic old forest lichens across climatic and successional gradients

Abstract

This paper aims to assess the influence of canopy cover on lichen growth in boreal forests along a regional forest gradient. Biomass and area gain, and some acclimation traits, were assessed in the old-forest lichens Lobaria pulmonaria (L.) Hoffm., Pseudocyphellaria crocata (L.) Vain., and Usnea longissima Ach. transplanted 110 days in three successional Norway spruce ( Picea abies (L.) Karst.) forest stands (clearcut, young, and old forest) repeated along a rainfall gradient (continental, suboceanic, and Atlantic zones) in Scandinavia. Lichen growth peaked in Atlantic rainforests with mean dry matter (DM) gain up to 36%–38%. The alectorioid lichen U. longissima showed the widest range of growth responses and no signs of chlorophyll degradation. Its highest DM gain consistently occurred in clearcuts, whereas the DM gain was close to zero in the shadiest young forest. The two foliose lichens L. pulmonaria and P. crocata exhibited maximal growth rates in old forests, but apparently growth was limited by low light even in old forests. Their DM gain was reduced in the most sun-exposed clearcuts due to chlorophyll degradation and was relatively high under closed young canopies, suggesting a better adaptation to shade. The lichen responses show that a high frequency and dominance of young and dense fast-growing forest stands at a landscape level are not compatible with large populations of these old-forest lichens and that a lack of lichens under an industrial forestry regime may not necessarily be determined by low dispersal efficiency only.

Effects of Modern Forest Management on Winter Grazing Resources for Reindeer in Sweden

“…60% have been found to provide suboptimal light conditions for mat-forming lichens (Jonsson Č abrajić 2009). Furthermore, low light restricts the growth of arboreal lichens particularly in young dense forests (Gauslaa et al 2007). The biomass of arboreal lichens is strongly related to the age of the forest stand.…”

The population structure of the lichen Lobaria pulmonaria in the middle boreal forests depends on the time-since-disturbance

“…This leads to the transformation of habitat conditions, mainly through changes in the level and quality of light intensity and humidity (Protopopov, 1975, Gauslaa et al, 2007. In aspen forests, the light intensity and the level of insolation throughout the year vary greatly due to leaf fall in autumn.…”

“…Experiments carried out in southern Norway demonstrated that the growth of Lobaria pulmonaria occurred throughout the year, but the maximum increase in biomass and area was observed from July to September (Larsson et al, 2012). It is known that intense direct sunlight can cause chlorophyll degradation in the L. pulmonaria thalli, and the consequences affect the growth of the species (Gauslaa et al, 2007). In the old-growth spruce forests, due to the edificatory role of spruce and the occurrence of several levels of tree canopy, a relatively stable microclimate occurs throughout the year.…”

Introducing Intensively Managed Spruce Plantations in Swedish Forest Landscapes will Impair Biodiversity Decline

“…Moreover, the low light availability and lack of sun exposure of retained trees and CWD within plantations may reduce the substrate quality for epiphytic lichens [40,41], and wood-living insects [42,43]. Hence, it seems likely that both the quality and function of key structural elements will be poorer inside than outside a plantation, implying that this type of conservational effort will be more effective if applied outside the plantations.…”